What you can say for it, is that it was free and near infinitely hackable.
Please tell me how we somehow have been hobbled despite having simple and clear pipelines setup that autobuild any branch we want and allow one click deploys to our preprod environment and automatically manage versioning and scalably handle load from "Literally zero" to "Everyone in the company wants to rebuild everything now" and goes down less than github.
What are we supposedly missing?
More importantly, what are we missing that tangibly improves results for our consumers?
Multibranch is still weird and obviously added-on.
Writing plugins is ugly.
Oldschool maven type jobs where you type shell script into a `<textarea>`? Yeah, let's not talk about those, but we don't have a single one left anymore.
It's too powerful and there are too many of its implementation details exposed to the user.
The DSL semantics can be weird with when things like params/env expansions in options block are evaluated.
If someone is forcing you towards high stakes tight-coupling with no thought whatsoever towards the lock-in, you should get it in writing that "we at ${org} are fully committed to ${vendor} with ${platform}, on ${cloud} using ${tech} come what may, now and forever" and lots of sign off so that everyone knows who to blame when this is inevitably wrong.
i don't know why it's not more popular.
I grant you pipelines are the best bit about ado, but the fact that you can’t test them is a pain.
And the webhooks and templating are pretty messy and unpleasant quickly.
We’re changing from ADO to GitHub (had to be an MS product for corporate) and the infra people are looking forward to GHA as they prefer their maintenance to ADO pipelines.